Truth be told i am just really bad at hardening off, i tend to put them out in full sun too early and they don't like it! They tend to get stunted and seem to take forever to grow.
I am not sure of the plant that you want to know about but i did have a prik-kee-nu (spelling) or rats turd as they are called go all haywire on me. It's leaves curled up horribly and it looked as though it had ingested radium, even the pods looked weird. I never figured out what caused it though as i had many plants growing in the same patch of soil and they grew really good, maybe a genetic malfunction or similar.
I would really like to know what happened to your plant though, it seems very strange that it would just up and die like that.